Weld efficiency indicator



Patented Dec. 7, 1937 UNITED STATES PATENT OFFICE Edward G. BuddManufacturing Company,

Philadelphia, Pa., a corporation of Pennsylvania Application May 1c,1932, Serial No. 611,223

5 Claims. (oi. 1711-311) This invention relates to welding and moreparticularly .to comparative welding indicators. This invention has forits principal object the construction of a means suitable for givingcomparative indications of the efliciency of the weld at the time of themaking of such weld in the manufacturing processes.

Another object of the invention is to construct such a device adaptablefor use in ordinary spot welding and of special value in the spotwelding of stainless steels, wherein the duration of the weld is ofextremely relatively short time, commensurately with relatively greatvalues of current. a

I attain the above enumerated desirable ob- .iects and others incidentalthereto, by a weld eflieiency indicator comprising a means responsive tothe energy condition of a spot welding circuit and means adapted toco-operate therewith and to indicate the condition of the weld.

My invention will be better understood from the following descriptionwhen considered in connection with the accompanying drawing and itsscope will be pointed out in the appended claims.

Referring to the drawing, attached hereto and made a part hereof, I haveshown schematically and in places partly in perspective, a mechanismconstructed in accordance with this invention. The various parts are notdrawn to scale and are broken at places to represent interconnectingparts.

The spot welding circuit l0 includes the transformer II, which is theimmediate source of energy for the electrodes l l comprising primary andsecondary windings l3 and M, respectively. The primary is connected to asuitable source of power not shown, through a suitable electromagnetically operated, momentary-contact switch III of a type operableto eflect a single momentary circuit closure upon each energization andde-energization, as through engagement of a stationarycontact 12 by awiping contact 13 insulated at 14 on one surface, and set at an angle toits path of travel so as to slide along the under surface of thestationary contact in electrical contact therewith on the up stroke, andto slide over the stationary contact with its insulated side in contacttherewith on the down stroke. The circuit closing device is operated,for example, by means of remote control from'the circuit IS, includingthe push-button station l6, a source of current H and the actuatingmagnet of the switch II. The operation of the push-button station ll toclose the current, therefore causes the-welda device creating suitablecomparative indicia for indicating the weld efiiciency or heat unitsvalue.

The weld may be incomplete because the welding current is insuflicientor the welding current may be too great and a burn may occur, themechanism thusserving as a criterion of comparative values. Theintermediate ground between these two comparative indications, is thearea wherein a good weld has occurred. The means I! as shown, comprisesa solenoid I8 and armature 19 arranged in magnetic co-operatlon.Obviously, although this solenoid is shown as having a relatively largenumber of turns, this is entirely dependent upon the relative values ofthe force reuired to operate the various parts, possibly a singleconductor without any turns under some circumstances would be sumcient.

As a means for visual comparative observation of the suitability andefficiency of the various welds, a mechanism comprising a plurality ofstep-by-step operated cylinders carrying a re cording tape II is used.To indicate the energy value of the spot welding circuit, the motion ofthe armaturepls is transmitted to a recording means 22 through anysuitable interlinkage 23. This visual record comprises a pluralityofspaced indieia 24 as shown. The part of the mechanism just described ismerely for a visual record and may comprise any other means suitable forsuch a purpose, it being incidental to the other parts of the device.The present invention is primarily adapted for the best psychologicaleffect for the machine operator so that he does not have to look up fromthe work.

The armature J9 is connected by linkage mechanism 25 to a ratchet 26,the mechanism acting in opposition to a compression spring or otherbiasing element @I. In secured relation to the ratchet is a contact arm28 which is adapted to normally rest in inactive position as at 29. Thiscontact arm has an energizing circuit 30 connected to a source of energyshown as a battery operates to raise the ratchet arm in'a verticaldirection in accordance with the energycf the weld. In the spot weldingof stainless'steels, the

' erotics,

short, possibly in the nature of one hundredth of a second so that themotion of the mechanism would be insufificient to proper use.

To adapt the mechanism to-this situation, I have shown a pawl mechanism60 comprising the pawl ll of bell-crank shape pivotally mounted at 42and moved to and retained in inoperative position by means of a spring38. This spring is strong enough to return the pawl to its inoperativeposition in which, it does not engage the ratchet it whenever magnet 45is de-energized. Connected at one end of the pawl is an armature itpositioned interiorly of a suitable solenoid t5 and connected to thepawl by a linkage (it. The solenoid is energized in the control circuit05 due to the operation of the push-button station it and inasmuch as itcontinues to be energized 28 moves from its normal position 29throughzones A, B, and C, corresponding respectively to a zone ofinsufficient or defective welding, a zone of good welding and a zone ofoverwelding or burning. The zones A and C have co operative therewithcontacts 5i and t ll. The contact 5i which would indicate a poor weld oran incom plete weld for the zone A has an indicia circuit including adelayed or retarded relay s2 and ground orv return connection 53. Thecircuit of operation for this zone would extend from one terminal of theenergy source 3i through the connection til to the arm 23, thence to thecontact 56 through the solenoid relayhl to the ground or return circuitInasmuch as the solenoid relay is retarded or delayed, the oper= ationof this relay will depend entirely upon the duration or dwell of thecontact arm upon the contact. 'Zll'ie time or this solenoid relay 52must becommensurate with the time values of the actuation of the weldingcircuit control and the duration of the welding circuit operation. Thesolenoid relay 52 may cause a signal device to be energized eitherdirectly or indirectlyas shown. The relay operation closes the signalcircuit across the contacts ti and operates a cell or other signalingmeans 52.

It the weld is a satisfactory weld, the pawl mechanism retains theratchet in its actuated position somewhere in the area between the zonesA and C; 'llhe contact area shown dotted is nor 0 cult through thecontact 55 because of the actua-' tion of the ratchet mechanism. Theratchet is again delayed or temporarily held in the actuated position bythe pawl and this time if the circuit connection is continued for aduration of tiinej such that the solenoid relay- 65. operates.thecontacts 58 are closed and a signal lid is actuated.

The actuation of the push-button station is relatively oi suficient timeduration sothat the the tive values will be appreciably greater and theadjustments of the various parts would be inherently difierent. The typeof relays and signaling devices. are subject to the substitution ofequivalents, for example electrically retarded or slow-to-operate relaysmay be substituted for the mechanically-retarded relays, consequentlyapparatus made in'accordance with the invention herein disclosed may in'appearance be entirely dissimilar, whereas in operation be an exactduplicate. A

The embodiment of the invention as illustrated and described has beenselected for the pur= pose of clearly setting forth the principlesinvolved. It will be apparent that the invention is susceptible of beingmodified to meet the different conditions encountered in its use and]!therefore aim to cover by the appended claims. all modifications withinthe true spirit and scope of the invention disclosed.

What I claim is:

l. In aweld energy consumption indicator the combination of a spotwelding circuit, a control circuit operable upon energlzation to supplya welding impulse to the welding circuit, indicating means associatedwith said welding circuit and responsive to the product of a functionoi'] the current flowing therein multiplied by the time of flow, meanscooperating with said responsive means retaining it temporarily in itslast actuated position; and means operable upon de-energization of thecontrol circuit to release said retaining means. 7

2. In a welding energy consumption indicator a spot welding circuit andmeans associated therewith responsive to the product oi a-function ofthe current fiow therein multiplied by the time of flow, a controlcircuit operable upon energization to supply a welding impulse to thewelding circuit, means cooperating with said responsive means andindicating individual consecutlve time-current-functlon products, meansH cooperating with said energy responsivemeane to retain it in actuatedposition, and means operable upon de-energization oi the control circuitto release said retaining means.

3. in a-weld energy consumption indicator the combination or" a spotwelding circuit, a control circuit operable upon energization to supplya welding impulse to the welding circuit, indicating means including asolenoid and armature associated with said welding circuit andresponsive in its degree of movement to the product of a function or"the current flowing therein multiplied by the time of now, meansincluding a ratchet and pawl cooperating with said armature andretaining it in its position of maximum movement, and means operableupon de=energization of the control circuit to release said r'etainingmeans.

4. In a weld energy coption indicator the combination or a spot weldingcircuit, a control circuit operable upon energization to supply awelding impulsetothe welding circuit, a solenoid,

connected with said welding circuit and hag an armature responsive inthe extent of its movement to the product of a function oi the.

current flowing therein multiplied by the time of flow, means forretaining said ll lli in actuated position, means selectively responsiveto successive degrees of movement of said armaption indicator lid thecombination of a spot welding circuit and intime-force responsive meanstemporarily in acdicating means associated therewith responsive tuatedposition, and means including a slow to the time-force product of briefenergy impulses responsive signaling device responsive only to in saidcircuit, a control circuit operable upon the retention of saidtime-force responsive means energization to supply a welding impulse tothe in a given position.

, 5 welding circuit, means arranged to retain said JOHN P. TARBOX.

